A Redox‐Activated MRI Contrast Agent that Switches Between Paramagnetic and Diamagnetic States

The design of molecular switches for the production of responsive or “smart” imaging agents is a major challenge. Of particular interest are agents that respond to biological redox environment to map those disease states that involve redox imbalances.[1] Redox imbalances may be triggered in many ways, including very low oxygen pressure or hypoxia in the case of solid tumors.[2] Importantly, the development of probes to map oxygen levels and corresponding redox status of tumor tissue may guide the development of tumor-selective drugs.[3]